Tubular wall construction



May 15, 1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 1Filed June 24, 1959 INVENTORS Rlchard H. Evans BY Leslie R PurpleATTORNEY May 15, 1962 R. H. EVANS ETAL 3,034,435.

TUBULAR WALL CONSTRUCTION Filed June 24, 1959 6 Sheets-Sheet 2 g io/cINVENTORS Richard H. Evans y Leslie P. Purple ATTORNEY May 15, 1962 R.H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 3 Filed June 24,1959 IINVENTORS v Rlchard H.Evans Leslle P. Purple ATTORNEY May 15, 1962R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 4 Filed June24, 1959 INVENTORS Rlchard H. Evans BY Leslie P. Purple ATTORNEY May 15,1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 5 FiledJune 24, 1959 May 15, 1962 R. H. EVANS ETAL 3,034,485

TUBULAR WALL CQNSTRUCTION Filed June 24, 1959 6 Sheets-Sheet 6 INVENTORSRichard H. Evans BY Lesl'geP. Purple ATTORNEY I United States Patent3,034,485 TUBULAR WALL CONSTRUCTION Richard H. Evans, Leatherhead, andLeslie P. Purple,

London, England, assignors to Bahcock & Wilcox, Limited, London,England, a company of Great Britain Filed June 24, 1959, Ser, No.822,481 Claims priority, application Great Britain Get. 17, 1953 7Claims. (Cl. 122-510) This invention relates to tubular vapor generatingand vapor heating units and ,more particularly to units adapted togenerate steam at high pressures and to superheat the steam to hightemperatures. In order to attain a required high temperature ofsuperheat, the use of a section of radiant superheater may provedesirable or necessary. The section of radiant superheater mayconveniently be suspended from above but the temperatures and pressuresto which the tubes of the superheater are raised render them liable tobecome distorted unless guide or positioning means are provided.

An object of the invention is the provision of a furna ce Wall includingboth vapor generating and vapor superheating tube lengths, in which thesuperheating tube lengths are maintained in position, but from which thesuperheating tube lengths may readily be removed.

The above object and other features and advantages are attained in avapor generating and vapor heating unit having a furnace chamber with awall including a row of upright vapor generating tube lengths withsuitable positioning means adapted to maintain the tube lengths inalignment with one another. Vapor superheating tube lengthsare disposedadjacent the vapor generating tube lengths and arranged to be exposed toradiant heat from the furnace chamber, the superheating tube lengthsbeing maintained in position adjacent vapor generating tube lengths bycoupling means which accommodate axial movements of the superheatingtube lengths relative to the vapor generating tube lengths due todifierential thermal expansion. The coupling means are such that asuperheating tube length may be uncoupled from the vapor generating tubelengths by an axial movement followed by a movement inwards of thefurnace chamber.

According to the present invention, a group of at least two of thesuperheating tube lengths extends between two spaced vapor generatingtube lengths and the coupling means, including a runner member, connectsto all the superheating tube lengths of the group.

The invention will now be described, by way of example, with referenceto the accompanying partly diagrammatic drawings in which:

FIG. 1 isa view of a fragmentary part of the furnace face of a furnacewall incorporating both vapor generating and vapor superheating tubelengths.

FIGS. 2A and 2B are sectional side elevations of a fragmentary portionof the vertical lower and'upper parts respectively of the wall taken onthe line II-II of FIG. 1, FIG. 2B being drawn to a larger scale thanFIG. 2A.

FIG. 3 is a sectional plan view of a fractional part of the wall takenon the line III-J11 of FIGS. 1 and 213.

FIG. 4 is a sectional plan view taken on the line 1VIV of FIG. 1.

FIGS. 5 and 6 are sectional plan views similar to the plan view of FIG.3, but respectively showing two modified arrangements of positioningmeans coupling the which over a lower part of the wall are tangentiallyarranged and which are provided on their outer sides in usual mannerwith buckstays (not show) by which the tubes are maintained in alignmentwith one another and, Where-bent from the plane of the wall, at theirdesired spacing. A nun sheet metal casing 1:12, FIG. 2A, is disfrom thefurnace chamber and is welded to channels 119 provided on certain of thetube lengths 101 at spaced intervals. The tube lengths 101 are connectedat their lower and upper ends to suitable inlet and outlet headers (notshown) respectively.

Superheating tube lengths 105, suspended from above in convent onalmanner and extending down the upper part of the furnace wall, aredisposed in groups of six at regular intervals across the furnace wallface. Thus every fourth vapor generating tube length 101 (designated101D) remains in the general plane of the furnace wall. Of the threeremaining tube lengths 101A, 101B, and 1tl1C in each set of four, thecenter tube length 101B is bent outwardly from the plane of the wall atone level and its two flanking tube lengths 101A, 101C are bentoutwardly in a similar manner at a somewhat lower level. The three tubelengths 101A, 101B, 101C above the higher of these two levels extendtangentially side by side to the top of the furnace wall. 7

Each group of six superheating tube lengths lies in one of the spaces soformed in the furnace wall face as a straight row of tangentiallyarranged tube lengths having their sides towards the furnace chamberarranged coplanar with the furnace chamber sides of the adjacent vaporgenerating tube lengths 101D. Thelower. ends of the superheater tubelengths 105 are welded to hollow stubs provided on a distributor 1&6and, with the tube lengths 191A, 101B and 101C bent in this manner,apertures 107, 108 and 109 (see FIG. 4) are left'respectively betweentube lengths 101D and 101A, tube lengths 101A and 101C, tube lengths101C and ltllD and these facilirate the passage of the tube lengths 105through the furnace wall.

Thus, identifying the superheater tube lengths 105 of a group from leftto right of FIG. 4 by the reference numerals 105A to 1055, tube lengths105A, 105C extend sidewardly through the aperture 107, tube lengths 1053and 105E extend first under the center vapor generating tube 13113 andthen through the aperture 108, while the tube lengths 105D, 105E extendsidewardly through the aperture 1S9. It will be noted that none of thesetubes rise towards the distributor 106, and therefore they can be fullydrained.

The sheet metal casing 102 extending over the part of the furnace Wallprovided with the superheating tube lengths terminates above thedistributor 106. To seal the Wall in the region of the distributor 106against the escape of hot furnace gases a two part cowl 117, 118 isprovided. Each part of the cowl is L-shaped in transverse cross-section.The upper part 117 is secured in gas-tight manner to a channel 119 towhich is welded the lower end of the adjacent part of the casing 102 andpart 117 is also Welded to a fin 120:extending from the distributor 106.The lower cowl is similarly secured in gastight manner to a Cl12111116l'121 welded to the upper end of a part of the casing 102 which extendsbelow the distributor 106 and'to a fin 122 extending from thedistributor. Below the distributor 106 the casing is welded to channels121 welded to the'tubes 101. The ends of the space between the cowls andthe furnace wall are closed in any suitable manner.

In theiembodiment of the invention illustrated, the vapor generatingtube lengths 101,11ave an outside diameter of 3 inches, the superheatingtube lengths 105 are of 1 /2 inches outside diameter.

Coupling means for maintaining the superheating tube lengths in positionadjacent the vapor generating, tube lengths while accommodating axialmovements of the superheating tube lengths relative to the vaporgenerating tube lengths due to differential thermal expansion areindicated generally at 130 in FIGS. 23 and 3. Such coupling means areprovided at vertically spaced intervals along the superheating tubelengths, and in the embodiment illustrated occur at intervals of 8feet.-

Referring to the embodiment of FIG. 3, each coupling be swung forwardlyinto the furnace chamber 103., By moving the superheating tube lengthsupwardly, the bar means 133 passes over the tops of theguide'members 139at each of the vertically spaced coupling means. The bar 133A is thenremoved laterally enabling the second bar 13313 to be moved in thedirection of the furnace chamber to disengage the stirrups 131 from thevertical slots 144 and then withdrawn laterally from the stirrups. Thesix superheating tube lengths are then unconnected with one ranotherandcan be replaced with new tube lengths, by a reversal of the aboveprocess, these new tube lengths then being welded at their ends to thestubs provided on the headers. i

The arrangement shownin FIG. 5 is'applicable to a furnace wall in whichthe superheating tube lengths extendnot only down an upper part of thefurnace wall but also down to the foot of that wall. In such a casethere is no need to bring the superheating tube lengths 105A to mainquite close to the remaining vapor generatingtube lengths 101D, giving arelatively thin wall. The vapor me'ans'comprisessix G-shaped stirrups orbrackets 131: 1

welded severally to the six superheating tube lengths 105, the stirrupsextending away from the furnace chamber 103 and tie bar or runner means133 extending through the stirrups 131, the runner means 133 beingformed with a head portion 135 having near its opposite ends shoulders137 facing the furnace chamber for engaging two guide members 139 weldedrespectively to two of the vapor generating tube lengths 101D. The guidemembers 139 connected to tubes 101D extend toward one another to reducethe free space between these tube lengths.

7 Thus each guide member 139 is in the form of a rectangular striphaving a thickness of /2 inch and 7 inches long, the presence of theseguide members thus reducing the free space between the two tube lengths101]) in the region of the coupling means from 9 inches to 8 inches. Thehead portion 135 has an overall length of 8% inches. The space 143, FIG.2B, inside each bracket or C-shaped stirrup 131 has a height of 3 /2inches and a depth of 2% inches, and the bar means 133 have a height of2 /2 inches. The bar means is in the form of two bars 133A and 133-B,the former being disposed closer to the furnace chamber 103. The bar13313 which is 1% inches thick, forms the head portion 135 and isprovided on its outer side with three vertical slots 144 foraccommodating two of the stirrups 131. The bar 133A, that nearer thefurnace chamber, is inch thick.

With the arrangement of vapor generating tube lengths 101 andsuperheating tube lengths 105 and coupling means 130 described above,the occurrence of differential thermal expansion between twosuperheating tube lengths 105 of the same group is accommodated by thearrangement of C-stirrups 131 and the bar means 133; Diiferentialthermal expansion between the superheating tube lengths 105 and thevapor generating tube lengths 101 is accommodated by sliding movement ofthe bar means 133 relative to the guide members 139. Such movement willnot be sufficient for the bar means to pass beyond the guide members139, so that at all times the superheating tube lengths 105 are held inalignment with one another by the bar means 133 and held in placerelative to the vapor generating tube lengths 101 by the coupling means.

When it is desired to replace one of the superheating tube lengths whichhas deteriorated in service, all six tubes of that group aredisconnected at their ends from the associated headers or distributors,this involving cutting each tube length at each end adjacent the stubprovided on the header. The superheating tube lengths 105 are then movedvertically upwards about three inches, so that the lower ends of thesuperheater tube lengths can generating tube lengths 101A, 10113 and101C are spaced apart and diametrically opposite fins 301 provided onthe tube length 101B and rearwardly directed fins 303 provided on thetubelengths 101D substantially close the inter-tube-length spacesbetween the tubes 101 and thus screen the thin metal casing 102 fromheat radiated by the superheating tube lengths.

Of the six superheating tube lengths 105A to 105F', tube lengths 105Band 105E are providedwith C-shaped stirrups 131 through whichristhreaded a bar or runner 133' having shoulders 137' arranged to contactguide members 139' Welded to the vapor generating tube lengths 101D.superheating tube lengths 105A, 1050* are secured to superheating tubelengths 1105B by short lengths of rod 305 which extend in the samedirection as the tube lengths and are welded to' the tube length 105Band either tube length 105A or 105C on the side of those tube lengthsremote from the furnace chamber 103.

' The guide member 139' is eight inches long and the coustirrups 131 donot fit within grooves in bar 133, this bar may be slid freeof thestirrups once the superheating tube lengths have been moved upwardly andforwardly into the furnace chamber, so releasing the tube lengths A to1051 a FIGS. 6 and 7 show an arrangement in which, of the sixsuperheating tube lengths 105A to 105F", the center four tube lengths1053" to 105E are provided with brackets or G-shaped stirrups 131 fittedseverally into slots 144" in bar 133B", and each of the end tube lengths105A", 105F" is connected to the adjacent tube length 10513" or 105E" byhinges 461 arranged'with their axes parallel to those of the tubelengths. Thus the hinge 461 joining lengths 105E, 105F" comprises threetubular members 461A, 461B, 461C threaded on a hinge pin 461D secured bya weld 463' to the upper member 461A. The hinge 461 is disposed on theside of the superheating tube lengths remote from the furnace chamber,the members 461A, 461C being welded to the tube length 105E" and themember 461A being welded to the tube length 105E". Apart from thesefeatures, the construction of FIG. 5 is similar to that of FIG. 3 andthe same numerals are used to denote similar parts.

In the various embodiments of the invention described above the couplingmeans between the superheating tube lengths and the vapor generatingtube lengths permit differential thermal expansion of those tube lengthsand'permit the removal of superheating tube lengths from the wall, aftercutting of their ends, by a vertical movement followed by an outwardmovement into the furnace chamber.

While the instant invention has been disclosed with reference to aparticular embodiment'thereof, his to be appreciated that the inventionis not to be taken as limited to all of the details thereof asmodification and variations thereof may be made without departing fromthe tube having an outer side, a readily detachable coupling.

means for maintaining said vapor heating tubes in relative alignment toeach other and to said vapor generating tubes, said coupling meansincluding aligned brackets mounted on the outer side of said vaporheating tubes, and a tie bar slidably received in said brackets andhaving end shoulder portions arranged to abuttingly engage said spacedvapor generating tubes for guiding the movement of said vapor heatingtubes relative said generating tubes during thermal expansion andcontraction thereof.

2. The invention as defined in claim 1 wherein said tie bar bracketshave a C-shaped formation with opposed leg portions connected to saidvapor heating tubes.

3. In a vapor generating and heating unit, a tubular wall arrangementdefining a boundary wall portion of a chamber, said tubular wallincluding a pair of spaced, longitudinally extending, vapor generatingwall tubes arranged tangent to the plane of said wall, a plurality oflongitudinally extending vapor heating tubes occupying the space formedbetween said vapor generating tubes, said vapor heating tubes beingdisposed substantially tangent to said plane of said wall, and couplingmeans to maintain said vapor heating tubes in relative alignment to eachother and to said vapor generating tubes, said coupling meansaccommodating longitudinal movement of said vapor heating tubes relativeto said vapor generating tubes and to each other as occasioned by thedifferential thermal expansion therebetween, said coupling meansincluding a guide member attached to each of said generating tubes so asto extend inwardly into the space formed between said generating tubesto reduce the distance therebetween, a plurality of brackets, each ofsaid backets'being connected to one of said vapor heating tubes on aportion thereof opposite that portion of the tubes tangent to the planeof said wall, and a tie means adapted to be received in said bracketsfor maintaining said vapor heating tubes in coplanar alignment, said tiemeans including a bar means having shoulder portions to accommodate saidguide members for maintaining said aligned vapor heater tubes inposition relative to said generating tubes.

4. The invention as defined in claim 3 wherein said bar means isprovided with a plurality of notches longitudinally spaced along theouter edge portion thereof and adapted to embrace said brackets, and asecond bar extending transversely within said brackets and disposedbetween the vapor heating tubes and said bar means to hold said barmeans-in position.

5. In a vapor generating and heating unit, a tubular wall arrangementdefining a boundary wall portion of a chamber, said tubular wallincluding a pair of spaced, longitudinally extending, vapor generatingwall tubes arranged tangent to the plane of said wall, a plurality oflongitudinally extending vapor heating tubes occupying the space formedbetween said vapor generating tubes, said vapor heating tubes beingdisposed substantially tangent to sm'd plane of said wall and couplingmeans to maintain said vapor heating tubes in relative alignment to eachother and to said vapor generating tubes, said coupling meansaccommodating longitudinal movement of said vapor heating tubes relativeto said vapor generating tubes and to each other as occasioned by thedifferential thermal expansion therebetween, said coupling meansincludinga guide member attached to each of said generating tubes so asto extend longitudinally thereof and inwardly into the space formedbetween said generating tubes to reduce the distance therebetween, abracket connected to eachrof said vapor heating tubes on a portionthereof opposite the portion thereof tangent to the plane of said wall,and a tie means adapted to be slidably received in said brackets formaintaining said vapor heating tubes in coplanar alignment, said tiemeans including a bar means having shoulder portions to accommodatesaid. guide members for maintaining said aligned vapor heater tubes inposition relative to said generating tubes.

6. In a vapor generating and heating unit, a tubular Wall defining aboundary portion of a furnace chamber, said tubular wall comprising arow of longitudinally extending vapor generating tubes arrangedsubstantially tangent to the plane of said wall, a portion of some ofthe vapor generating tubes in said row being outwardly displaced out ofthe plane of said wall intermediate the length thereof to form a spacebetween a pair of'vapor generating tubes extending in the plane of saidwall, a plurality of vapor heating tubes extending longitudinally insaid space between said vapor generating tubes, said vapor heating tubesbeing substantially tangent to the plane of said wall and supported insaid space independently of said generating tubes, a detachable couplingmeans for maintaining said vapor heating tubes in relative coplanaralignment in the space formed between said pair of vapor generatingtubes, said coupling means accommodating relative thermal expansion ofsaid vapor generating and vapor-heating tubes, and said coupling meansincluding aligned brackets connected to said vapor heating tubes, a tiebar extending transversely of said vapor heating tubes and slidablyreceived in said brackets, and said tie bar having end shoulder portionsarranged to abuttingly engage said spaced vapor generating tubes formaintaining said vapor heating tubes in alignment relative to each otherand to said spaced vapor generating tubes.

7. In a vapor generating and heating unit, a tubular wall defining aboundary portion of a furnace chamber, said tubular wall comprising arow of longitudinally extending vapor generating tubes arranged tangentto the plane of said wall, a portion of some of the vapor gen eratingtubes in said row being laterally displaced out of t the plane of saidwall intermediate the length thereof to form a space between a pair ofvapor generating tubes extending in the plane of said wall, saidlaterally displaced portion of the generating tubes extendinglongitudinally in a plane spaced from and substantially parallel to theplane of said wall outwardly of said chamber, a plurality of vaporheating tubes extending longitudinally in the space formed betweenadjacent pairs of spaced vapor generating tubes, said vapor heatingtubes being substantially tangent to plane of said wall and supported insaid space independently of said generating tubes, and readily removablecoupling means for maintaining said vapor heating tubes in relativecoplanar alignment in the space between said pair of vapor generatingtubes, said coupling means accommodating for relative thermal expansionof said vapor generating and vapor heating tubes, said coupling meansincluding a guide member longitudinally attached to the spaced pair ofsaid generating tubes extending tangent to the plane of said wall, saidguide means extending inwardly into the space formed between said pairof vapor generating tubes to reduce the distance therebetween, aplurality of C-shaped brackets, each of said brackets having opposed legportions and a connected bight portion, and the leg portions of each ofsaid C-shaped brackets being connected to one of said vapor heatingtubes to form a closed loop there with, each of said brackets beingconnected in transverse alignment to a portion of said vapor heatingtubes opportion tangent to said displaced tubes, and a second bar,

extending transversely of said loops and occupying the remainder of saidloop, said second bar including an edge portion tangent to said vaporheating tubes. w 7

. References Cited in the file of this patent UNITED STATES PATENTS1,802,750 Black -Q Apr. 28, 1931 2,228,953 Hackett Jan. 14, 19412,244,144 Drewry June 3, 1941 2,354,222 Shellenberger July 25, 19442,681,641 Andrew et a1. Iune 22, 1954 2,834,324

Schoessow May 13, 1958 myr-

